My girlfriend and I were celebrating the day of her birth with a lovely off road adventure. Once at the top, we decided to hike at the peak of Kebler Pass while witnessing Aspen trees as wide as truck tires. The towering forest, mingling with surrounding chirps of the mid-summer alpine black squirrels, made for one of the most delightful afternoons in my life.

Kebler Pass near Crested Butte Colorado is one of the better places to go to take photos of the yellow aspen trees of autumn in Colorado. The road from Crested butte is a grated dirt road that is always in exceptional condition.
The best area for viewing the aspen groves is from the summit of the pass west from late afternoon to sunset. there are huge groves that span the entire valley and all the trees change color at the same time.
The road leaves Crested Butte and climbs up into the mountains, after a few miles it turns to a well maintained grated dirt road all the way to the other side of the pass.
There are great hiking trails and lakes to see, you could even mountain bike the road but the car traffic in the fall could be a bit dangerous.
The best lenses to take are wide angle for general landscape work and a longer 70-200mm range lens. There are tons of great photo opportunities with a medium to long zoom lens.
I have included a photo map with pins where i took photos in the link to make finding a few locations a bit easier. There is an established US Forest Service campground at Lost Lake Slough reservoir with quite a few campsites available for a nominal cost per night.
A few tips for finding the right time to go is to search photo sharing websites for "kebler pass" then sort by date taken. The end of September is generally a reliable time for great fall colors. It can snow at any time in September so be prepared for that.